Stoker apparatus



Feb- 20, l1945. R. A. FoREsMAN Erm. 2,369,957

sToKEYR APARA-Tus Filed Dec. s1. `1940 5 sheets-snaai 1 Feb. zo, 1945. RA FORESMAN ETAL 2,369,957

STOKER APPARATUS 4Filed Deo. 3l, 1940 5 Sheets-Sheet 2 INVENTORS -RoaenrR. Fo seaman ATTORNEY R. A. oREsMAN Erm. 2,359,957

Feb. zo, 1945.

STOKER APPARATUS 5 Sheets-Sheet 5 Filed Dec. 3l, 1940 Tn... .E E smnnRRHH ORnC Y. To 5 E NF... .N E. R VH. @o mTam .U ,nu A E Tm a N Rp..

Feb 20 945 R. A. FoREsMAN Erm. 2,369,957

STOKER APPARATUS Filed Dec. 3l, 1940 5 Sheets-Sheet 5 man WITNESSES:

Patented Fea/2o, .1945 2,369,957

STOKER APPARATUS Robert A. Foresman, Prospect Park, Donald J. Mosshart,Ardmore, and Arthur F. Schultz, Springfield, Pa., assignors toWestinghouse Electric & Manufacturing Company,l East Pittsburgh, Pa., acorporation of Pennsylvania Application December 31, 1940, Serial No.372,640

17 Claims.

This invention relates to stokers, more :particularly to progressivefeed stokers and means for disposing of the ash from the discharge endsof such stokers, and it has for an object to improve the eiiiciency ofthis type of apparatus.

Another object of the invention is the provision of an extension grateconstruction for use with progressive feed stokers, which constructionhas improved agitating and pushing action.

These and other objects are effected by the invention as will beapparent from the following description and claims taken in connectionwith thev accompanying drawings, forming a part of this application, inwhich:

Fig. 1 is a perspective view of a progressive feed stoker embodying theimproved extension grate construction;

Fig. 2 is a longitudinal sectional view through a furnace containing aStoker such as shown in Fig. 1;

Fig. 3 is a plan view of the extension grate construction with themoving bars thereof in retracted forward position;

Fig. 4 is a view similar to Fig. 3 but with the moving bars in theirextended rearward posi-l tion;

Fig. 5 is a transverse sectional view taken along the line V-V of Fig.3, looking in the direction of the arrows;

Fig. 6 is a view similar to Fig. 5, but with the moving bars in adifferent position;

Fig. 'l is a transverse sectional view of one of the moving grate bars,the View being taken along the line VII-VII of Fig. 6;

Fig. 8 isa fragmentary view similar to Fig. 7, but showing a gratebarwith the central. portion omitted;

Fig. 9 is a side elevational view of a modified type of static-narygrate bar; and,

Fig. 10 is a transverse sectional vie'w taken along the line X-X'of Fig.9,1ooking in the direction of the`arrows.

An extension grate construction for'use with a progressive feed stokerhas two main functions: the first being to break up and agitate the bedof burning fuel passing thereover to permit uniform ow of air throughthe same for promoting combustion, and the second being to positivelyeject the ash and non-combustible refuse as it reaches the discharge endof the extension` grate.

In view of these functions, the extension grate may be considered tocomprise first and second zones of action, considered in the directionof (Cl. 11G- 44) `tory. member for imparting reciprocation to all pointnear the discharge end of the extension grate, the fuel fed theretoshould be completely consumed, hence the grate action in this zoneshould be primarily that' of agitation to break up any clinkerformations and to provide 'for ample penetration of air to the fuel bedto insure complete combustion ofthe fuel prior to its leaving this zone.

If the extension grate properly performs the above functions in itsfirst zone, the second zone, which extends from the discharge end of thefirst zone to the ash pit, will receive only ash and non-combustiblerefuse. This being the case, the grate action in the second zone shouldbe primarily that of pushing to eject the ash and refuse.

Therefore, the present invention provides, for

use at the discharge end of a progressive feed stoker, an extensiongrate construction comprising a first; transversely-extending row ofgrate bars, a number of said bars being adapted to reciprocate and beinginterspersed among the remaining bars, which are stationary. This rstrow of bars provides a first zone in which the main action applied to'the fuel bed is that of agitation, although, of course, definite feedingaction is also present. Following this first row of grate bars is asecond transverse row ofbars, 'all of which are adapted to reciprocateand are provided with rearwardly-facing fuel-contacting and pushingsurfaces, which surfaces are inclined sufficiently to insure positiveejectment of the ash and refuse fed thereto from the first row ofgrate-bars constituting the first zone. X

'I'he construction includes a single reciprocaof the reciprocatory gratebars, and an angularly adjustable support for the rearwardends of thegrate bars of the last row, whereby the pushing leffect of these barsmay be vvaried in accordance the discharge end of the underfeed sectiontoa with the angular adjustment of the supporting member therefor.

Referring now to the drawings more in detail, vand with particularreference to Figs. 1 and -2, the reference numeral I Il indicates afurnace in its entirety. The furnace comprises a front-wall II. sidewalls I2 and a rear or bridge wall I3. 'I'he furnace walls dene acombustion chamber I4 within the lower portion o1' which is disposed astoker I5 comprising an underfeed section I6 `of alternately arrangedvretorts I1 and tuyre rows I8, the Stoker having an overleed. section I9which comprises the subject-matter of the present invention. An airchamber 20 is provided 'beneath the stoker and serves to supply air forsupporting combustion.

In operation, fuel 'is fed from a hopper 2| into the ends of the retortsI1 by means of primary rams 22 reciprocating within a ram box 23, andthe fuel is advanced along the retorts and forced upwardly over and ontothe tuyre rows Il by 'means of secondary rams 24 reciprocating within`ond row comprises a plurality of reciprocatory bars 30.

A cross-head 32, adapted to reciprocate in a direction longitudinally ofthe stoker, extends transversely of the extension grate construction andis supported for sliding movement upon a bearing plate 33 carried by theframe structure apart laterally a distance equal to or greater than thewidth of the forward ends of the reciprocatory bars 28, normallydisposed therebetween. It will be apparent that, in order to remove anyreciprocatory bar 28, it is only necessary to lift the rearward endthereof a sumcient distance to remove the lugs 5| from their recesses52, whereupon the bar may be moved rearwardly to withdraw the forwardend thereof from between the adjacent brackets 51.

It .will be noted that the discharge end of the progressive feed Stokerhas a rearwardly-projecting lip structure l0 overhanging the forwardends of all of .the grate bars 23 and 29 of the iirst'row 25. Thisoverhanging structure $0 is disposed so close to the forward ends of thegrate barswhich it overlies that there is'not suilicient space to raisethe upper ends ofthe stationary bars enough to separate -theupwardlyprojecting lugs 58 from their mating recesses 59. However,

' bar may be slid rearwardly until its forward end 34, 35, and 3B. Meansfor imparting reciprocap tory motion to the cross-head 32 is providedand comprises a plurality of rods 31 connected at onel thetransversely-extending shaft 40, which is mounted for limitedoscillatory movement in the bearing member 4 I. This bearing member maybel bolted, as at 42, or otherwise secured, to the stoker frame 43.

Suitable means are provided for imparting limited oscillatory movementtothe shaft 40, which means comprises the lower portion of the doublecrank arm 39, the rod 45 and the adjustable link 45 and rod 41 havingadjustable connection through the eccentric 48 with the stoker engine50.

In order that reciprocation ofthe cross-head 32 may impartcorresponding-motion to the reciprocatory first grate bars 28, thelatter are p rovided on the under faces of their rearward ends withdepending lugs 5| adapted to be received n mating recesses 52 in theupper surface of the cross-head. For manufacturing reasons, it may bedesirable to form these recesses 52 as slots open at the forward `edgeof the cross-head and to close the same by a transversely-extendingplate 53 bolted, or otherwise secured, to the crosshead (Fig. 1). Theforward ends of the reciprocatory first bars'23 rest upon rockers 54,which are supported through arms 55 upon the trans is clear of theoverhanging .structure 80. The rearward ends of the stationary bars 23merely rest upon the cross-head 32, which slides or reciprocatestherebeneath.

In the second or last row.21, the grate members 3i! are pivotallysupported at their forward ends by brackets llv formed integral with, orpermanently attached to, the cross-head 32. rEach versely-extendingshaft l40 vcarrying .the double crank arms 39. The bearing surfaces ofthe rockers 54 and the length of thearms 55 areso de'- signed andproportioned that there is substantially pure rolling action between therockers 5.4

and the forward ends of the reciprocatory bars l individually supportedby laterallyspacedbrackets 51, bolted or otherwise secured'to thestolzerv frame structure. Each bracket has an upwardlyextending lug 5ladapted to be received in a downwardly-opening recess in the lower faceof the forward end of each of the stationary bars 29. A The brackets l1and their lugs Il are spaced bracket 5I has a pair of upwardly-extendinglugs or flanges having aligned transversely-extending openings 53therethrough, adapted to receive suitable means, such as pivot pinsA(not shown). for pivotally supporting and securing the forward ends ofthe bars 30 therein.

The rearward ends of the bars 30 are supported by, and adapted to slideupon, an ash-supporting structure 65. This ash-supporting structurecomprises a base plate 65 pivotally mounted, as at 61, on a bracket 88secured to the frame member 34. A link 59 is pivotally connected to anarm 10 by pin or bar means 1|,"the arm 10 being clamped or flxedlysecured to a shaft 12 extending transversely of the furnace andpreferably having one end'thereof extending through the furnace sidewall, whereby it may be given a limited rotary movement from without thefurnace by an operator. It will be apparent that the ash-supportingstructure may be angu- 'larly adjusted about the axis at 81 by limitedpartial rotation of the operating shaft 12. The

ash-supporting structure has two bearing surfaces for the grate bars 30,one surface being at 13 on thevbase plate BB, and the other beingprovided by a sectional ash-supporting member 14 having' an uppersurface 15. Reference to Figs. 5 and 6 will indicate that when theash-supporting i member 14 is in a substantially horizontal positionadjacent the upper limit of its adjustment. the last grate members 30will bear upon the surface 15, while when the ash-supporting structureis lowered, as illustrated in dotted lines in Fig. 5, the bars 30 willbear upon the surface 13. Obviously, there is an intermediate positionof the ash-supporting structure at which the bars 30 will bear in partupon the surface 13 and in part upon the surface 14, depending uponwhich portion of their reciprocatory stroke or length of travel they aregoing through.

Referring to Figs. 2, 5 and 6, it will be seen that the furnace rear orbridge wall I3 has a curved portion 'l1 disposed in overlying relationto the ash-support member 14. Thecurved portion Tl and theash-supporting member 'I4 define therebetween a transversely-extending,longitudinally-converging ash discharge outlet 18.`

As indicated by the dot and dash line shown inl Fig. 5, this convergingpassage 18 may be adjusted so that it is converging orconvergingdiverging, depending upon the angular adjustment of theash-supporting member. Preferably, the portion ll of the rear wall I3which overlies or is in close proximity to the ash discharge outlet 18is water cooled, as by means of tubes 19. In some cases it may bedesirable to provide the curved portion 'll of the furnace rear wallwith a depending lip or nose block 80 to catch, or retard the dischargeof, unconsumed fuel which would otherwise pass through the dischargeopening 18 to the ash pit.

Referring to Figs. 7, 8, 9, and 10, there is provided a novel compositeconstruction of grate members 28 and 29, the construction shown in Fig.7 being that of a reciprocatory grate bar 28. The bar is made up of sidesections A and C and an intermediate section B, these sections beingheld together by a plurality of bolts 8l extending through abuttingbosses 82 and 83 carried by the sections B, and A and C, respectively.Preferably, 'the members A, B and C are provided, on their adjacentfaces, with a plurality of pins o'r knobs 84 and a plurality of beads orribs 85. The members A and C .are provided on their outer sides withhorizontally-disposed ribs 8B, and,` as indicated in Figs. 3 and 4,these ribs on adjacent reciprocatory and stationary bars overlap, theribs on the stationary bars being at different heights than those-on theadjacent reciprocatory bars. In order that the reciprocatory bars may beremoved in the manner previously explained, that is, by lifting therearward ends sufficiently to remove the depending lugs 5| from theirmating recesses 52 and the1i-.moving the bars rearwardly. the ribs 86are so arranged that there will be no interference of overlapping ribsduring lifting of the rearward ends of the bars. To this end, thevertical spacing of the ribs increases from the forward end or upperpart of the bars to the rea-rward end or lower part thereof,corresponding to the greater vertical lifting movement of the rearwardend relative to the forward end. v(Figs. 5 and 6.) l

The pins 84 and ribs 85 and 86 are provided I for the purpose ofdistributing the air and cooling the grate bars. as more fully set forthin Patent comprising a member B' identical with the central member B ofFig. 7. except that it.is designed as a stationary grate bar rather thana reciprocatory bar and therefore has the downwardlyopening recess 59 inthe lower face of its forward end for the reception of theupwardly-extending supporting'and securing lug 58.

It Will be seen that, by the provision of three standard grate barmembers A, B and C, com- At the bottom of the bar are a pluralitylposite or unitary grate bars of 3, 2 or 1 parts having correspondingwidths, maybe provided. The particular construction or width of gratebar to be used will depend largely upon the operating conditions of thefurnace and stoker and the particular grade of fuel used. While theconstruction herein illustrated shows the first row 26 of the extensiongrate construction made up of alternate reciprocatory and stationarygrate bars, it will be apparent that the invention is not limited tothis particular arrangement, but will cover any other arrangementwherein a number of reciprocatory bars are interspersed among a numberof stationary bars.

It will be apparent from consideration of Figs. 3 and 4 that when Vthereciprocatory bars 28 are in their forwardmost or retracted position,the upper surfaces thereof are disposed below or forward of thecorresponding surfaces of the stationary bars 29. Of course, when thereciprocatory bars are in their `rearwardmost or projected position,their upper surfaces lie above and rearwardly of the correspondingsurfaces of the stationary bars. This construction results in sired,therefore, that only such limitations shall be placed thereupon as arespecifically set forth in the appended claims.

What we claim is:

l. In a progressive feed stoker, an extension grate structure disposedat the discharge end of said stoker, said structure comprising iirstvand second transverse rows of grate bars, a crosshead extendingtransversely of the structure and serving to support the rearward endsof the grate bars of theffirst row and the forward ends of the gratebars of the second row, means for securing the bars of the second row tothe cross-head, means securing alternate bars of the iirst row to thecross-head, and means through which there may be imparted to thecross-head straight-line reciprocatory movement longitudinally of theStoker whereby the bars of the second row and alternate bars of thefirst row will be reciprocated relative to the remaining bars of thefirst row.

2. Structure as specified in claim 1, including vertically-adjustablesupporting means for the rearward ends of the grate bars of the secondrow.

3. In a progressive feed stoker, an extension grate structure disposedat the discharge end of said stoker, said structure comprising atransverse row of rst grate bars, a transverse row of second grate bars,means securing a number of the first grate bars against movementlongitudinally of the Stoker, means for reciprocating the 'remainingfirst grate bars and the second grate ing first bars againstreciprocatory movement with the rearward ends of said remaining barsresting upon the cross-head, whereby reciprocation of the latter causesreciprocation of the alternate bars connected thereto; atransverselyextending row of second grate bars pivotally connected'a'ttheir forward ends to the cross-head;

and a vertically-adjustable structure for slidably I supporting therearward ends of said second bars. 7. Structure as specified in claim 6,wherein at the forward limit of movement of the reciprocating rst gratebars the upper surfaces thereof are retracted below the correspondingsurfaces of the remaining iirst grate bars, and at the rearward limit ofmovement of said reciprocating first grate bars the upper surfacesthereof are projected beyond the corresponding surfaces of the remainingfirst grate bars.

8. In a progressive feed stoker, an extension grate structure disposedat the discharge end of said stoker: said structure comprising avertically-adjustable ash plate spaced rearwardly of the stoker; across-head adapted to be reciprocated in a direction longitudinally ofthe stoker disposed intermediate and spaced from the ash dump plate andthe stoker; a plurality of parallel firstv grate bars disposed in'side-by-side relation ceived in downwardly-opening mating notches in thelower faces of the forward ends of said stationary bars, and the meansfor securing the rearward ends of the reciprocatory iirst bars to thecross-head comprises a plurality of depending lugs on the lower faces ofthe rearward ends of said reciprocatory bars adapted to be received inmating openings in the upper surface of the cross-head.

l2. In a progressive feed stoker, an extension grate constructiondisposed at the discharge end of said Stoker; said structure including atransverserow of parallel grate bars disposed in sideby-side relation,said row comprising a number of reclprocatory bars interspersed among anumber of stationary bars; supporting means for the rearward ends of thegrate bars and adapted to be reciprocated in a direction longitudinallyof the Stoker; supporting means for the forward ends of the grate barsand comprising a. plurality of laterally-spaced upwardly-extending lugsadapted to be received in mating grooves ln the lower faces of theforward ends of said stationary bars, said lugs having spacestherebetween corresponding to the widths of the interspersedreciprocatory grate bars and vadapted to normally receive the forwardends of the latter; and mating vertical lug and recess connectionsbetween the rearward ends of the reciprocatory bars and theirreciprocatory supporting means, whereby the reciprocatory bars may beremoved from the and bridging the space between the underfeed sectionand the cross-head, said plurality of first grate bars comprisingalternate reciprocatingand stationary bars' having their rearward endssupported bythe cross-head; fixed supporting means carried by the stokerfor the forward ends of the stationary iirst bars; movable supportingmeans for the forward ends ofthe reciprocatory ilrst bars; meanssecuring thev rearward ends of said reciprocatory first bars to 'thecross-head; and a plurality of reciprocatory second grateybars disposedin side-by-side relation and bridging the space between the cross-headand the ash plate rwith their forward ends pivotally connected to saidcross-head and their rearward ends slidably supported by said ashplate.

9. Structure as specified in claim 8, wherein the fixed supporting meansfor the forward ends of the stationary first bars comprises a pluralityof .upwardly-projecting lugs adapted to be received in correspondingvshaped downwardlyopening notches in the lower faces of the forward endsof said stationary bars.

l0. Structure as specified in claim 8,- wherein the means for securingthe rearward ends of the reciprocating first bars to the cross-headcomprises a depending lug on the lower face of the rearward end of eachof said bars adapted to be received in corresponding openings in theupper surface of the cross-head.

l1. Structure as specified in claim 8, wherein the fixed supportingmeans for the forward ends of the stationary first bars comprises aplurality of upwardly-projecting lugs adapted to be reextension grateconstruction by raising the former relative to the latter to separatethe mating lugs and recesses.

13. In a progressive feed stoker having an extension grate constructiondisposed at the discharge end of said stoker; said constructionincluding a transverse row of parallel grate bars disposed inside-by-side relation, said row comprising a number of reciprocatorybars interspersed among a number of stationary bars; supporting meansfor the rearward ends of said reciprocatory and stationary bars adaptedto be reciprocated in a direction longitudinally of the stoker;supporting means for the forward ends of the reciprocatory grate bars;supporting means for the forward ends of the stationary grate barscomprising a plurality of laterally-spaced upwardly-extending lugsadapted to mate with downwardly-opening grooves in the lower faces ofthe forward ends of said stationary bars, the spaces between adjacentlugs being at least as great as the width of the stationary barssupported by said lugs and being adapted to normally receive the forwardends of the interf spersed reciprocatory bars, removal of saidlastmentioned bars providing for lateral sliding of the adjacentstationary bars off the lugs and into the spaces therebetween fromwhence they may be freely removed; and means connecting the rearwardends of the reciprocatory bars to their reciprocatory support, wherebyreciprocation of `the latter produces reciprocation of the former,

of the first row and all of the bars of the second row being mounted formovement bodily in the general direction of fuel feed for advancing andejecting ash from the stoker; means for eecting such movement of thegrate; a normally station ary member disposed transversely of thedirection of fuel feed at the discharge end of the stoker and providinga supportl for the ash coming from the Stoker, the forward end of themember extending beneath and forming a bearing support for the rear endof the extension grate; adjusting means for moving the` ash-supportingmember l disposed that at one limit of angular adjustment of thesupporting member the rear end of the extension grate bears only on thesurface lying in one 'of said planes, at the other limit of angularadjustment of the supporting member the grate bears only on the surfacelying in the other of said planes, and at an intermediate point ofadjustment of the vsupporting member the grate bears on the surfacelying in one piane during 'a portion of its bodily movement and bears onthe surface lying in the other plane during the remainder -of the bodilymovement.

17. Structure as specified in claim 15, including means supporting theforward ends vof the bars of the second row in the extension grate con'struction for movement in an approximately horizontal plane at alltimes, and the rearward ends of said last-named bars being adapted tomove in a plane varying from horizontal to an incline of severaldegrees, dependin'g upon theA angular adjustment of the ash-supportingmember upon which they bear.

ROBERT A. 1=0Rns1vm1\r.` DONALD J. MossHART. ARTHUR F. soHULTz.

